Substituted 2-amido quinoxalines

ABSTRACT

Compounds of the formula   WHEREIN R1 is alkyl, alkenyl, alkynyl, cycloalkyl, alkoxyalkyl, chloroalkyl, bromoalkyl, or cyanoalkyl; R2 is hydrogen, chlorine, bromine, or fluorine; R3 is alkyl or alkenyl; and n is 0 or 1 are useful as fungicides. A representative compound is 3-amino-6chloro-2-propionamidoquinoxaline.

United States Patent [191 Sam [ SUBSTITUTED 2-AMIDO QUINOXALINES [75] Inventor: Donnie Joe Sam, Newark, Del.

[73] Assignec: E. I. du Pont de Nemours & Company, Wilmington, Del.

[22] Filed: Feb. 19, 1974 [21] Appl. No.: 443,198

Related U.S. Application Data [63] Continuation-impart of Ser. No. 366,877, June 4,

1973, abandoned.

OTHER PUBLICATIONS Chemical Abstracts, Elina et al., 1966, Vol. 65, 713a. lbid, Elina et al., 1963, Vol. 59, 12807c.

[ July 15, 1975 Primary Examiner-Donald G. Daus Assistant Examiner-David E. Wheeler [57] ABSTRACT Compounds of the formula 0 l! q NHCR l 0 .L

ll N C 2 r 15 C 1. n

wherein R is alkyl, alkenyl, alkynyl, cycloalkyl, alkoxyalkyl, chloroalkyl, bromoalkyl, or cyanoalkyl; R is hydrogen, chlorine, bromine, or fluorine; R is alkyl or alkeny]; and n is 0 or 1 are useful as fungicides. A representative compound is 3-amino-6-chloro-2- propionamidoquinoxaline.

6 Claims, No Drawings 1 SUBSTITUTED Z-AMIDO QUINOXALINES CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 366,877, filed June 4, 1973, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a novel class of quinoxalines and their use as fungicides. Schipper and Day describe imidazoquinoxalines in J. Am. Chem. Soc. 73, 5672 (1951), but no fungicidal activity of these compounds is mentioned and no quinoxalines of this invention are mentioned.

SUMMARY OF THE INVENTION Injury to plants due to fungi is prevented by application to the locus to be protected a fungicidally effective amount of the novel compounds described below. The compounds described below have systemic fungicidal activity. Thus, the compounds can be applied directly to the plant parts to be protected, other parts of the plant, or to the media in which the plants are growing. All of these sites of application are included in the term applying to plants as used herein. Compositions consisting essentially of these compounds are useful for controlling fungi in plants. The fungicidal compounds are quinoxalines represented by the formula:

11 P, N\ 2 I O I III N n c-n H I n where:

R is alkyl of one to four carbon atoms, cycloalkyl of three to six carbon atoms, alkenyl of two to four carbon atoms, ethynyl, alkoxyalkyl of two to three carbon atoms, chloroalkyl of one to two carbon atoms, bromoalkyl of one to two carbon atoms, or cyanoalkyl of two to three carbon atoms;

R is hydrogen, chlorine, bromine, or fluorine;

R is alkyl of one to seven carbon atoms or alkenyl of two to four carbon atoms; and

n is O or 1; provided that the total number of carbon atoms in R, and R is less than or equal to nine.

Of the R substituents, preferred are alkyl of one to two carbon atoms when n is 1; when n is 0, alkyl of two to three is preferred.

Of the R substituents, preferred is chlorine.

Of the R substituents, preferred are alkyl of one to five carbon atoms.

Preferred are compounds where n is 0.

Most preferred compounds are 3-amino-6-chloro-2- propionamidoquinoxaline and 6-chloro-3-hexanamido- Z-propionamidoquinoxaline.

DESCRIPTION OF THE PREFERRED EMBODIMENTS For the sake of clarity, the nomenclature used throughout this case is based on the position numbering system for quinoxalines shown below:

N1-C-R3 v as 6-substituted compounds of type II. Obviously. compounds differing only in position of R are the same as each other when R is hydrogen (e.g., la is the same as II when R H).

O u R N 2 NHCR O In O H II N NC R N C R n O R H n 2 N 3,895,011 5 6 8 X ri(R COCl) C R mFfclinei I 3, IX 2 11 C001 N NH V II (firidinei N NHCR. Q n i ll C'R'I O l N NH XI N NH R Vlll II X C-R (l-n) 3 The compounds of this invention are made by the processes illustrated by the following equations, wherein the substituents are as previously defined:

The starting material for reaction 1, a 2,3- diaminoquinoxaline (IX), is prepared as follows:

H H 1. N NH2 50 NH 2 N NH NH 0 H HN NH N NH2 0 O H N H H H3COC-COCH3 R k cock R 2 1 2 N NH N H H 2 The o-phenylenediamine and substituted phenylenediamine reactants in the above reaction (4) are commercially available or easily synthesized by those skilled in the art. The dimethyl oxaldiimidate reactant can be prepared by the reaction of cyanogen in an excess of methanol, preferably with a basic catalyst. Temperatures and pressures in this reaction are not critical, but temperatures and pressures should be selected to handle gaseous cyanogen conveniently, as is known to those skilled in the art. Dimethyl oxaldiimidate can be isolated from the reaction mixture by distillation. The compound boils at 65C at 43 mm pressure. The dimethyl oxaldiimidate can also be formed and reacted with the o-phenylenediamine in situ. Reaction 4 above proceeds in a methanol solvent system at room temperature. A small amount of acid is required. The preparation of 2,3-diaminoquinoxalines is also described in Hinsberg and Schwantes, Ber. 36, 4039 (1903) and Schipper and Day, J. Amer. Chem. Soc. 73, 5672 (1951).

Reaction 1 above is conveniently run at room temperature in an inert solvent, such as tetrahydrofuran, dioxane, or acetonitrile, for an overnight (ca. hrs.) period. Temperature of the reaction mixture can be varied from about 15 to 35C., reaction time from about 4 to 48 hours, and mole ratio of anhydride to diaminoquinoxaline from about 1:1 to 4:1. Order of addition of reactants is not critical. The acid anhydride can be substituted by one equivalent of the corresponding acid chloride and an acid acceptor such as pyridine. Note that Schipper and Day, J. Amer. Chem. Soc. 73, 5672 (1951) teaches that reflux of 2,3- diaminoquinoxalines with acid anhydrides produces imidazoquinoxalines. Thus, high temperatures should be avoided in reaction 1.

Reaction 2 is accomplished by permitting a compound of type X to react with an equivalent amount or slight excess of an appropriate acid chloride in the presence of an equivalent amount or excess of a tertiary amine (such as pyridine, triethylamine, or lutidine). The tertiary amine can be employed as the solvent for X during addition of the acid chloride, or it may be added to a mixture of the acid chloride and X. The reactants can be diluted with an inert solvent such as tetrahydrofuran, dioxane, or acetonitrile; and the reaction temperature should be maintained between 0 and 25 by external cooling. A reaction time of one hour is normally sufficient.

Reaction 3 represents a convenient method for the preparation of compounds of the type X1, in which the two amide groups are identical. The reaction of two equivalents or an excess of an appropriate acid chloride with lX in the presence of two equivalents or an excess of a tertiary amine under the conditions described for reaction 2 affords compounds of the type XI. The conversion of X] to X can be achieved by the selective cleavage of one of the amide moieties. Thus, X is obtained when X1 is permitted to react with one equivalent of a secondary amine such as pyrrolidine or morpholine in an inert solvent such as tetrahydrofuran or acetonitrile at ambient temperature for l to 7 days.

Reaction 1 is the method of choice for the preparation of compounds of type X when R contains from one to three carbon atoms. For the preparation of compounds of type X where R contains more than three carbon atoms, reaction 3 is the preferred method.

In the examples which follow, all percentages and parts are by weight and temperatures in degrees centigrade, unless otherwise indicated.

EXAMPLE 1 3-Amino-6-chloro-2-propionamidoquinoxaline A suspension of 5.0 parts of 6-chloro-2,3- diaminoquinoxaline in parts of tetrahydrofuran (THF) and 15 parts of propionic anhydride was stirred overnight at room temperature. The reaction mixture was filtered and the filter cake was washed with n-butyl chloride and dried to yield 3.7 parts of yellow solid. Recrystallization from THE gave pale yellow crystals of 3-amino-6-chloro-2-propionamidoquinoxaline, m.p. 300.5-302.5.

EXAMPLE 2 6-Chloro-3-hexanamido-2propionamidoquinoxaline A suspension of 50 parts of 3-amino-6-chloro-2- propionamidoquinoxaline in 1,000 parts of pyridine was cooledto 5 in an ice bath. A solution of 96 parts of hexanoyl chloride in 88 parts of tetrahydrofuran was added as quickly as possible with good cooling to prevent the temperature from rising above 25. The reaction mixture was stirred for 10 minutes and then poured into 2,500 parts of ice water. The yellow gum which separated was removed by filtration and washed with water and then dissolved in 2,700 parts of methylene chloride. The methylene chloride solution was washed in succession with 1,000 parts each of water, 5% aqueous hydrochloric acid, water, 10% aqueous sodium carbonate, and water. The methylene chloride solution was dried (MgSO and evaporated. The residue was recrystallized from 1:4 ethyl acetate-benzene, the solid filtered off, and washed with ether to yield 8 parts of 6-chloro-3-hexanamido-2- propionamidoquinoxaline, m.p. 158160, as a colorless solid.

EXAMPLE 3 2,3-Bis-(acetamido )-6-chloroquinoxaline To a solution of 33 parts of acetyl chloride in 44 parts of tetrahydrofuran were added 10 parts of 6-chloro- 2,3-diaminoquinoxaline. The temperature rose to 35. The reaction mixture was cooled to 5 in an ice bath and stirred vigorously during the addition of a solution of 15 parts of pyridine in 22 parts of tetrahydrofuran. The cooling bath was removed and the reaction mixture was stirred for 6 hours. The solvent was evaporated and the residue was partitioned between 340 parts of methylene chloride and 200 parts of water. The methylenechloride layer was separated and washed in succession with 200 parts each of water, 10% aqueous sodium carbonate, water, 3% aqueous hydrochloric acid, and water. The methylene chloride solution was dried (MgSO and evaporated. The residue was triturated with ether, filtered off, and washed with ether to yield 1.6 parts of 2,3-bis-( acetamido)-6- chloroquinoxaline as a tan solid, m.p. 178 dec.

EXAMPLE 4 6-Chloro-2,3-bis-(valeramido)quinoxaline A suspension of 100 parts of 6-chloro-2,3- diaminoquinoxaline in 1,000 parts of pyridine was cooled to 5 in an ice bath. A solution of 152 parts of valeryl chloride in 130 parts of tetrahydrofuran was added quickly with good cooling to prevent the temperature from rising above The reaction mixture was stirred at ambient temperature for 1 hour and then poured into 2,500 parts of water. The solid which separated was removed by filtration and washed with water, methanol, and then ether. The crude product was recrystallized from methanol to yield 55 parts of 6- chloro-2,3-bis-(valeramido)quinoxaline, m.p. l7l-l73, as a colorless solid.

EXAMPLE 5 3-Amino-6-chloro-2-valeramidoquinoxaline A solution of 12 parts of 6-chloro-2,3 bis(- valeramido)quinoxaline and 2.5 parts of pyrrolidine in 220 parts of tetrahydrofuran was permitted to stand at ambient temperature for 7 days. The solution was then poured into 750 parts of water and the solid which separated was removed by filtration and washed with water, pressed dry, and washed with hexane. The crude product was dissolved in 108 parts of boiling ethyl acetate and the resulting solution filtered. Upon addition of 100 parts of hexane and subsequent cooling, the solution deposited 3 parts of 3-amino-6-chloro-2- valeramidoquinoxaline as a pale yellow solid, mp. 224228C.

By the general procedures of Examples 1 through 5, by use of the appropriate starting materials, the following compounds can be prepared:

2-acetamido-3-aminoquinoxaline, m.p. 319, dec.

3-aminc-6-bromo-2-propionamidoquinoxaline 3-amino-6-fluoro-2-propionamidoquinoxaline 3-amino-2-propionamidoquinoxaline Z-acetamido-3-amino-6-ch10roquinoxaline, mp

340C 3-amino-2-butyramido-6-chloroquinoxaline, m.p.

3-amino-2-butyramidoquinoxaline 2-acrylamido-3-amino-6-chloroquinoxaline 2-acrylamido-3-aminoquinoxaline 3-amino-6-chloro-2-crotonamidoquinoxaline 3-amino-2-crotonamidoquinoxaline 3-amino-6-chloro-2-methacrylamidoquinoxaline 3-amino-6-chloro-2-seneciamidoquinoxaline 3-amino-6-chloro-2-propiolamidoquinoxaline 3-amino-6-chloro-2-cyclopropanecarboxamidoquinoxaline 3-amino-6-chloro-2-cyclohexanecarboxamidoquinoxaline 3-amino-6-chloro-2-( a-methoxyacetamido )quinoxaline 3-amino-6-chloro-2-( a-ethoxyacetamido )quinoxaline 3-amino-2-( a-methoxyacetamido )quinoxaline 3-amino-6chloro-2-(achloroacetamido)quinoxaline 3'amino-2-( B-bromopropionamido)-6- chloroquinoxaline 3-amino-6-chloro-2-(a-cyanoacetamido)quinoxaline 10 3-amino-6-chloro-2-(,B-cyanopropionamido)quinoxaline 3-amino-6-chloro-2-(B-chloropropionamido)quinoxaline 3-amino-2-(a-bromoacetamido)quinoxaline 2,3-bis(acetamido)quinoxaline 3-amino-6-chloro-3-octanamidoquinoxaline 2,3-bis(propionamido)quinoxaline 2,3-bis(acetamido)-6-fluoroquinoxaline 6-bromo-2,3-bis(propionamido)quinoxaline 6-chloro-2,3-bis(propionamido)quinoxaline 2,3-bis(butyramido)-6-chloroquinoxaline 6-chloro-2,3-bis(isobutyramido)quinoxaline 3-acetamido-6-chlore-2propionamidoquinoxaline 6-chloro-2-cyclopropanecarboxamido-3- propionamidoquinoxaline 6-chloro-2-cyclopentanecarboxamido-3- propionamidoquinoxaline 2,3-bis(acrylamido)-6-chloroquinoxaline 6-chloro-2,3'bis(crotonamido)quinoxaline 6-chloro-2-acetamido-3-seneciamidoquinoxaline 6-chloro-2-crotonamido-3-propionamidoquinoxaline 6-chloro-2-propiolamido-3- propionamidoquinoxaline 6-chloro-2-(a-methoxyacetamido )-3- propionamidoquinoxaline 6-chloro-2-(a-ethoxyacetamido)-3- propionamidoquinoxaline 6-chloro-2-(a-chloroacetamido)-3- propionamidoquinoxaline 6-chloro-2(B-chloropropionamido)-3- propionamidoquinoxaline 2-(a-bromoacetamido)-6-chloro-3- propionamidoquinoxaline 2-(a-bromopropionamido)-6-chloro-3- propionamidoquinoxaline 6-chloro-2-(a-cyanoacetyl)-3- propionamidoquinoxaline 6-chloro-2-(B-cyanopropionamido)-3- propionamidoquinoxaline The compounds of this invention possess outstanding fungicidal activity when employed to prevent or mitigate damage to plants by fungi. The compounds are particularly effective against powdery mildew fungi, Erysiphaceae. Plants are protected by preventive (before infection) and curative (after infection) treatments. Disease control is provided throughout a plant by systemic action. Isolated treatments protect across (from ventral to dorsal and dorsal to ventral) a leaf and both acropetal (upward) and basipetal (downward).

The compounds of this invention control a wide variety of powdery mildew fungus diseases of foliage, fruit and stems of growing plants without damage to the host.

The compounds of this invention provide protection from damage caused by powdery mildew fungi when applied to the plants by the methods described hereinafter and at a sufficient rate to exert the desired fungicidal effect. They are especially suited for the protection of living plants.

Living plants are protected from fungi by applying one or more of the compounds of this invention to the soil in which they are growing or in which they may subsequently be seeded or planted; or to plant reproductive parts prior to planting; as well as to foliage, stems and fruit of the living plant. Living plants can also be protected by dipping the root system or physically injecting the chemical or chemicals into roots or stems.

Soil applications are made from dusts, granules, pellets, slurries or solution. Rates for application of the compounds of this invention to soil in which plants are or will be growing range from 1 to 100 parts per million by weight of the soil in which the roots are or will be growing.

Rates for application to seeds, ,tubers, bulbs or other plant reproductive parts, range from l to 1000 grams of active compound of this invention per 50 kilograms of planting material treated. Applications are made from dusts, slurries or solutions.

Rates for application of the compounds of this invention to foliage,-stems and fruit of living plants range from 0.1 to kilograms of active ingredient per hectare. The optimum amountwithin this range depends upon a number of variables which are well known to those skilled in the art of plant protection. These variables include, but are not limited to, the disease to be controlled, weather conditions expected, the type of crop, stage of development of the crop, and the interval between applications. Applications within the range given may need to be repeated one or many more times at intervals of l to 60 days. Applications are made from dusts, slurries or solutions. 7

The compositions of the invention can contain, in addition to the active ingredient of this invention, conventional insecticides, miticides, bactericides, nematicides, fungicides, or other agricultural chemicals such as fruit set agents, fruit thinning compounds, fertilizer ingredients and the like, so the compositions can serve useful purposes in addition to the control of fungi. The proper choice of amounts is readily made by one skilled in the art of protecting plants from pest depredations.

The outstanding control of powdery mildew by the compounds of this invention was illustrated by a greenhouse preventive test. The compounds listed in the following table were sprayed as water suspensions on cucumber seedlings to the point of run-off. Treated seedlings were dried and inoculated with conidia of the fungus, Erysiphe ciclzoracearum. After 8 days incubation in a greenhouse, seedlings which were not treated were 85 to 100 percent covered with powdery mildew. Disease control readings were made by estimating the percentage of leaf surface free of disease.

Percent Powdery Mildew Control Concentration of Active Compound Active Compound 80 PPM 16 PPM 3.2 PPM 3-amino-6-chloro-2-pro- 100 100 93. pionamidoquinoxaline 2-acetamido-3-amino- 96 5 3 l0 quinoxaline 6-chloro-3-hexanamido-2- 100 100 86 propionamidoquinoxaline greenhouse until untreated plants were covered with disease. Disease control readings were made by estimating the percentage of leaf surfacefree of disease. The untreated plants were covered with powdery mildew. Cucumber plants growing in soil containing 1 ppm of either of the test chemicals supported only an occasional mildew colony (90% control). Cucumber plants growing in soil containing 5 ppm of-eith er of the test chemicals'were free of mildew control).

The preventive control of another powdery mildew onapple seedlings was illustrated in a greenhouse test. A water suspension of 3-amino-6-chloro-2- propionamidoquinoxaline at 400 ppm was sprayed to the point of .runoff on potted apple seedlings. The treatedseedlings were driedand inoculated. with conidia of the fungus Podosphaera Ieucotricha. After lO days incubation in the greenhouse, seedlings which were not treated were more than 90% covered with powdery mildew. The treated plants had only an occasional fungus colony (97% control).

Useful formulations of the compounds of this invention can be prepared in conventional ways. They include dusts, granules, pellets, solutions, suspensions, emulsions, wettable powders, emulsifiable concentrates and the like. Many of these can be applied 'directly. Sprayable formulations can be extended in suitable media and used at spray volumes of from afew pintsto several hundred gallons per acre. High-strength compositions are primarily used as intermediates for further formulation. The formulations, broadly, contain about 1% to 99% by weight of active ingredient(s) and 'at least one of (a) about 0.1% to 20% surfactant(s) and (b) about 5% to 99% solid or liquid diluent(s). More specifically, they will contain these ingredients in the following approximate proportions.

Percent by Weight Lower or higher levels of active ingredient can, of course, be present depending on the intended use and the physical properties of the compound. Higher ratios of surfactant to active ingredient'are sometimes desirable and are achieved by incorporation into the formulation or by tank mixing.

Typical solid diluents are described in Watkins, et al., Handbook of Insecticide Dust Diluents and Carriers, 2nd. Edn., Dorland Books, Caldwell, NJ. The more absorptive diluents are preferred for wettable powders and the denser ones for dusts. Typical liquid diluents and solvents are described in Marsden, Solvents Guide, 2nd. Edn., lnterscience, New York, 1950. Solubility under 0.1% is preferred for suspension concentrates; solution concentrates are preferably stable against phase separation at 0C. McCutcheons Detergents and Emulsifiers Annual," Allured'Publ. Corp., Ridgewood, New Jersey, as well as Sisely and Wood,

Encyclopedia of Surface-Active Agents, Chemical Publ. Co., 'Inc New York, 1964, list surfactants and recommended uses. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth, etc. Preferably, ingredients should be approved by the US. Environmental Protection Agency for the use intended.

The methods of making such compositions are well known. Solutions are prepared by simply mixing the ingredients. Fine solid compositions are made by blending and, usually, grinding as in a hammer or fluid energy mill. Suspensions are prepared by wet milling (see, for example, Littler, U.S. Pat. No. 3,060,084). Granules and pellets may be made by spraying the active material upon preformed granular carriers or by agg'lomeration techniques. See J. E. Browning, Agglomeration, Chemical Engineering, Dec. 4', 1967, pp. l47ff. and Perrys Chemical Engineers Handbook, 4th. Edn., McGraw-l-lill, N.Y., 1963, pp. 8-59ff.

For further information regarding the art of formulation, see for example:

J. B. Buchanan, US. Pat. No. 3,576,834, Apr. 27,

1971, Col. 5 Line 36 through Col. 7 Line 70 and Ex. l-4, 17, 106, 123-140.

R. R. Shaffer, US. Pat. No. 3,560,616, Feb. 2, 1971,

Col. 3 Line 48 through Col. 7 Line 26 and Examples 3-9, 11-18.

E. Somers, Formulation, Chapter 6 in Torgeson, Fungicides," Vol. 1, Academic Press, New York, 1967.

The following examples further illustrate the formulation of compositions within the scope of this invention.

EXAMPLE 6 Wettable Powder 3-amino-6-chloro-2-propionamidoquinoxaline 40% dioctyl sodium sulfosuccinate 1.5% sodium ligninsulfonate 3% low-viscosity methyl cellulose 1.5%

attupulgite EXAMPLE 7 Aqueous Suspension 3-amino-6-chloro-2-propionamidoquinoxaline 25% hydrated attapulgite 3% crude calcium ligninsulfonate 10% sodium dihydrogen phosphate 0.5% water 61.5%

The ingredients are ground together in a ball or roller mill until the solid particles have been reduced to diameters under 10 microns.

EXAMPLE 8 Oil Suspension Z-acetamido-3-aminoquinoxaline 25% polyoxyethylene sorbitol hexaoleate 5% highly aliphatic hydrocarbon oil The ingredients are ground together, in a sand mill until the solid particles have been reduced to under about 5 microns. The resulting thick suspension may be applied directly, but preferably after being extended with oils or emulsified in water.

water sprayed on to accomplish granulation. When most of the material has reached the desired range of 1.0 to 0.42 mm. (U.S.S. No. 18 to 40 sieves), the granules are removed, dried, and screened. Oversize material is crushed to produce additional material in the desired range. These granules contain 12% active ingredient.

EXAMPLE l0 Dust fi-chloro-3-hexanamido-Z-propionamido- 10% quinoxaline attapulgite 10% talc The active ingredient is blended with attapulgite and then passed through a hammermill to produce particles substantially all below 200 microns. The ground concentrate is then blended with powdered talc until homogeneous.

EXAMPLE 1 1 Wettable Powder 6-chloro-3-hexanamido-2-propionamide- 50% quinoxaline sodium alkylnaphthalene sulfonate 5% partially desulfonated sodium 3% lignosulfonate kaolinite clay 42% The ingredients are blended, coarsely hammermilled and then air-milled to produce particles of active which are less than 20 microns in diameter. The product is reblended before packaging.

I claim: 1. A compound of the formula H N NHCR R 2 l Q \N I! (H 2 wherein R, is alkyl of one to four carbon atoms, cycloalkyl of three to six carbon atoms, alkenyl of two to four carbon atoms, ethynyl, alkoxyalkyl of two to three carbon atoms, chloroalkyl of one to two carbon atoms, bromoalkyl of one to two carbon atoms or cyanoalkyl of two to threev carbon atoms; R, is hydrogen, chlorine, bromine or fluorine; R is alkyl of one to seven carbon atoms or alkenyl 5 of two to four carbon atoms; and

n is 0 or 1; provided that the total number of carbon atoms in R, and R is less than or equal to nine. 2. A compound of claim 1 where n is 0. 3. A compound of claim 2 where R, is alkyl of two to three carbon atoms and R is chlorine.

4. The compound of claim 2, 3-amino-6-chloro-2- propionamidoquinoxaline.

5. A compound of claim 1 wherein n is 1, R, is alkyl of one to two carbon atoms, R, is chlorine and R is alkyl of one to five carbon atoms.

6. The compound of claim 5, hexanamido-2-propionamidoquinoxaline.

6-chloro-3- 

1. A COMPOUND OF THE FORMULA
 2. A compound of claim 1 where n is
 0. 3. A compound of claim 2 where R1 is alkyl of two to three carbon atoms and R2 is chlorine.
 4. The compound of claim 2, 3-amino-6-chloro-2-propionamidoquinoxaline.
 5. A compound of claim 1 wherein n is 1, R1 is alkyl of one to two carbon atoms, R2 is chlorine and R3 is alkyl of one to five carbon atoms.
 6. The compound of claim 5, 6-chloro-3-hexanamido-2-propionamidoquinoxaline. 